Figure 8.

Endogenous TL1A is important for early induction of IL-9^high ILC2s after allergen exposure. (A) Treatment schedule of naïve WT mice. (B) IL-9 mRNA levels in the lungs analyzed by qPCR at different time points after a single allergen exposure. Data are expressed as relative to IL-9 mRNA levels in mice treated with PBS. (C–H) Flow cytometry and frequency of IL-9^highLin⁻ cells among live CD45⁺ cells (C and D) and IL-9^high ILC2s among live ILCs (Lin⁻CD45⁺CD90.2⁺ cells) (E and F), flow cytometry (G), and MFI of IRF4 expression in ILC2s (H), in the lungs of WT mice 6 h after a single i.n. administration of A. alternata extract (12.5 μg), with (αTL1A mAb) or without (Iso, isotype control mAb) TL1A blockade. Numbers inside outlined areas indicate the percent of cells in the relevant gate (C, E, and G) and data are representative of two (G) or three (C and E) independent experiments. Each symbol represents an individual mouse and data are pooled from three (D and F) or two (B and H) independent experiments. Data are expressed as mean (±SEM) with P values determined by one-way ANOVA followed by Tukey’s multiple-comparisons test (B) or unpaired two-tailed Student’s t tests (D, F, and H): ns, not significant, *** P < 0.001, **** P < 0.0001.